Among glittering guests expected at last night’s Broadway opening of “I’ll Eat You Last,” about Sue Mengers, was a married couple the agent introduced. “I was with Sue at the Grill in LA [in] 1989,” recalled Mitch Glazer, creator of Starz series “Magic City.” When he spotted “a beautiful woman sitting with her agents,” he asked Mengers who she was. “Kelly Lynch . . . You want her?” Mengers shot back. “I said, ‘Yes. I really do!’ ” Glazer further remembers. “By the time I got back to my house, there was a message from Sue with Kelly’s number and Sue telling me Kelly was expecting my call.” The couple married in 1992. “Every anniversary I write to my wife, ‘God bless Sue Mengers!’ ” Glazer said, “the greatest thing an agent’s ever done for me.” Lynch stars on Glazer’s show, which starts a new season in June. Also expected at Bette Midler’s opening as Mengers last night were Ralph Lauren, Calvin Klein, Barry Diller, David Geffen, Ali MacGraw, Sting, Faye Dunaway, Ellen Barkin and Martin Short.